The present invention relates generally to an amphibious vehicle and, more particularly, to an amphibious vehicle having a pair of reversely flighted outriggers operably connected to either side of a buoyant hull to propel the vehicle over both water and land.
It is well know in the prior art such as U.S. Pat. Nos. 4,476,948 and 5,203,274 to propel an amphibious vehicle with a pair of single-flighted parallel augers. These and other prior art amphibious vehicles employing single-flight auger-type propulsion have the disadvantage of poor maneuverability and propulsion in water making them impracticable for long distances or narrow straits.
A major drawback of these prior art devices is the inefficiency with which rotational movement of the augers is transferred into propulsive movement. The lead on the flights is typically too long to give adequate pulling power or too short to give adequate speed.
Another drawback of these prior art amphibious vehicles is the relative instability of the vehicles. The typical prior art amphibious vehicles employ only the two augers for flotation or, alternatively, attach the augers within recesses of the hull, thereby providing very little lateral stability against capsizing under turbulent conditions. Yet another drawback of the prior art devices is the complexity with which a dual auger amphibious craft must be operated. The independent operation of the augers required to accomplish tight turns and land travel typically require separate controls for each auger thereby making the vehicle difficult to control for the novice.
The difficulties encountered in the prior art discussed herein above are substantially eliminated by the present invention.